Founder Elon Musk told a space station research conference Wednesday that he wants to set realistic expectations for the flight later this year from Cape Canaveral.

He noted that this approach will be used by "the next generation of SpaceX rockets and spacecraft", but didn't disclose further details. But the capsules will continue to land via parachute, unless SpaceX does another about-face.

One major reason is that it would be very hard to design a propulsive landing that would meet safety certifications.

"It would have taken a tremendous amount of effort to qualify that for safety, particularly for crew transport", Musk said in a speech at the conference.

The project would have involved putting thrusters in the bottom of the Dragon so the capsule could fire them during descent on Mars and touch down gently. It wouldn't then make sense to use the Dragon to land on Mars. "It doesn't seem like the right way of applying resources right now".

After the interview, Musk tweeted out additional information: He does intend to do propulsive landings on Mars with future SpaceX crafts - just not the Dragon.

Musk also announced that he may update his Mars colonization plans at the upcoming International Astronautical Congress in Adelaide, Australia, this September.

Meanwhile, Musk said that SpaceX is getting closer to being able to recover the fairing, a nosecone that sits atop the rocket to protect the payload during launch.

Musk said he would consider the flight a success if the rocket gets off the launch pad without burning it up. The vehicle, which is essentially three Falcon 9 cores strapped together, is supposed to fly for the first time later this year. "[Falcon Heavy] requires the simultaneous ignition of 27 orbit-class rockets", he said, and added that there's a "lot of risk associated with Falcon Heavy".